Experimental Design

What is the purpose of experiments?

• To study causal relationships

• To collect data

• To manipulate variables

• To analyze statistics

How many key steps are there in designing an experiment?

• 3

• 4

• 5

• 6

What is the first step in designing an experiment?

• Define the variables

• Write the hypothesis

• Design the treatments

• Measure the dependent variable

What is the purpose of a control group?

• To compare results

• To manipulate variables

• To measure the dependent variable

• To assign subjects to treatment groups

What is the difference between a completely randomized design and a randomized block design?

• The number of treatment groups

• The type of variables used

• The method of assigning subjects to groups

• The measurement of the dependent variable

How can extraneous variables be controlled in an experiment?

• By manipulating the independent variable

• By measuring the dependent variable

• By assigning subjects to treatment groups

• By statistically controlling for them

What is the purpose of measuring the dependent variable?

• To manipulate the independent variable

• To control extraneous variables

• To assign subjects to treatment groups

• To collect data on the outcome

How can the validity of an experiment be improved?

• By increasing the sample size

• By using a control group

• By randomizing the treatment assignment

• By measuring the independent variable

What is the purpose of a null hypothesis?

• To establish causation

• To predict the outcome

• To compare treatment groups

• To test for no effect

How can the external validity of an experiment be improved?

• By manipulating the independent variable

• By precisely measuring the dependent variable

• By controlling confounding variables

• By varying the independent variable